ES2346738T3 - PROCEDURE AND ELECTRONIC DEVICE TO INVEST THE ROTATION OF AN ENGINE. - Google Patents

Abstract

A method and an electronic apparatus for reversing the rotation of a two-stroke internal combustion engine (P1, C1; P2, C2), provided with an ignition system (20,21) powered by a permanent magnet voltage generator (1, 2). The electronic apparatus comprises a microprocessor control unit (5) programmed for controlling the sparking both during forward and backward rotations, and for controlling the reversal rotation procedure of the engine (P1, C1; P2, C2). The reversal procedure is controlled on the basis of information obtained from a first binary signal (I1) emitted by a bistable magnetic sensor (7) activated by the magnetic flux of the generator (1, 2), and from a second binary signal (I2) correlated to the polarities of output voltage (vg) of the voltage generator (1, 2). The original forward or backward rotation is made to reverse by providing a sparking delay, and subsequently generating an advanced spark while the engine (P1, C1; P2, C2) is still rotating in the original direction.

Description

Procedure and electronic device for reverse the rotation of an engine.

Background of the invention

This invention relates to a process. to reverse the rotation and to an electrical device to control the ignition of an internal combustion engine type two times, and in particular refers to an electronic device Microprocessor controlled to reverse motor rotation, both single-cylinder and two-cylinder type, obtaining the necessary information about the phase and direction of rotation of the motor using a particular magnetic sensor and the same generator voltage that supplies power to the engine ignition circuit. The invention can be used to reverse rotation in motors for snow caterpillar vehicles, small vehicles, water scooters and in all those applications that require an investment Controlled the rotation of a two-stroke engine.

Systems have been proposed in many different ways mechanical or electrical and electronic devices of complexity variable to control the investment of a combustion engine internal two-stroke

In particular, the documents US-A-5,036,802, US-A-5,782,210 and US-A-5,794,574, show several devices for reversing the rotation of an engine, which comprise a microprocessor properly programmed for monitor the speed and direction of rotation of the motor, as well as to manage the engine ignition, both during its rotation forward as during its reverse rotation, based on information obtained by sampling the output of a generator voltage, or based on pulse signals, separated from the generator voltage signals, supplied by a pair of Inductive trigger circuits properly offset for provide the control microprocessor with related information with the direction, rotation speed and motor phase.

In general, investment devices previously known require complex electronic solutions, expensive that are somewhat unreliable or, in any case, difficult to configure when the investment must be carried out at very low rotation speeds; in particular, in previously known rotation inversion devices, the ignition must be deactivated beforehand to make the engine Reduce speed and pulse signals are generated by usual inductive type magnetic detectors, which have the ability to detect the variation in the generated magnetic flux by them, caused by the passage of a tooth provided on the peripheral surface of the voltage generator rotor which normally supplies power to the engine ignition.

It is also known that in the sensors that they work by this principle, every variation in the magnetic flux originates the generation of an electrical impulse that has a polarity corresponding to a positive or negative variation of the magnetic flux; that is, a positive signal and, respectively, a negative signal depending on whether the tooth is entering or leaving the magnetic field of the sensor, regardless of the direction of rotation Therefore, using a single sensor this type is not possible to know the direction of motor rotation under all conditions that may exist in practice in the time of investment; in fact, if the moment of investment coincides with an intermediate position of the tooth, with respect to the axis of the sensor, that is when the tooth has already engaged magnetically with the sensor, it will emit in any case two signals of opposite polarities, in the same way as the case in that the tooth continues its rotation forward, doing so impossible to recognize the direction of rotation and control effectively Engine ignition

In the electronic control of the investment of Rotation of an engine is also necessary to be fully aware of the angular position of the motor in relation to the thermal cycle, because it is an essential fact not only to control the ignition on both directions of motor rotation, but also to control the entire investment procedure and subsequent retries in case of one failed.

In the devices described in the patents previous, the amplitude of the impulse generated by the type sensors inductive is proportional, as is known, to the flow derivative magnetic, that is, it depends on the speed at which the tooth enters and, respectively, exits the magnetic field of the sensor; by consequently, for low rotation speeds the amplitude of the momentum generated can sometimes prove to be too low to allow it to be recognized by the control unit precisely as a result of an investment attempt that, as is obvious, It implies an instant of time in which the velocity is zero.

Whereas the devices previously mentioned refer precisely to these impulses to get information about the phase and direction of rotation of the motor, this It can be considered as its critical state.

Consequently, inductive type sensors normally used in control devices for inversion of the rotation of an internal combustion engine described in the patents previously mentioned, they are extremely difficult to configure to get a reliable investment procedure, and they are structurally complex and expensive due to the need to use several sensors of a relatively high cost.

Objects of the invention

The main object of this invention is provide a procedure and an electronic device to reversal of the rotation of a two internal combustion engine times, and to control the ignition, by means of which it is possible to have a high degree of certainty by recognizing both the angular position as the direction of rotation of the motor, regardless of the direction of forward or forward rotation back and the rotation speed of the same engine, and which ensures a high degree of reliability of the investment procedure.

A further object of the invention is to provide a procedure and an electronic device of the type above mentioned, by which it is possible to recognize if an attempt of reversing the motor rotation has been successful or failed, and in the latter case allow a subsequent attempt or more attempts

A further object of the invention is to provide a apparatus for reversing the rotation of an engine and for controlling the respective ignition system that, in addition to being more highly reliable, it is also structurally simple and cost effective relatively small

Brief Description of the Invention

These and more objects can be achieved through a procedure to reverse the rotation of an engine of internal combustion according to claim 1, and by means of a electronic microprocessor controlled device according to the claim 9.

According to a first aspect of the invention, it has been provided a procedure to reverse the rotation of a two-stroke internal combustion engine that has a generator voltage to generate an alternating voltage that has different polarities for an ignition circuit, and a control device electronic comprising a microprocessor control unit to control the alternating voltage supplied to said circuit of on, in which the rotation inversion is made after a reduction in engine rotation speed, characterized by the stages of:

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provide said control apparatus a bistable sensor that has first and second conductive states, and cyclically switch the sensor between said first and second states during engine rotation;

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generate a first binary signal that it has first and second operational levels correlated with said first and second conductive states of the bistable sensor;

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generate a second binary signal that It has first and second operational levels correlated with the polarities of the alternating voltage supplied to the circuit switched on;

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detect the speed and direction of motor rotation, based on information obtained by the unit microprocessor control from said first and second binary signals;

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reduce the rotation speed of engine while still turning in the direction detected, delaying the ignition circuit spark formation with with respect to a top dead center of the engine; Y

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reverse rotation forming the spark in advance with respect to said neutral upper engine.

According to an additional feature of the invention, an electronic apparatus is provided to reverse the rotation of a two-stroke internal combustion engine that has at least one two-cylinder piston unit times, comprising:

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a engine ignition circuit;

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a voltage generator that has a permanent magnet rotor and a stator equipped with a winding to generate an alternating voltage to supply power to the ignition circuit;

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media to supply phase signals correlated with the direction and motor rotation speed; Y

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a microprocessor control unit, to control the phases of the ignition circuit and to make a reversal of rotation of the engine.

characterized by understanding:

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a bistable sensor that has first and second conductive states, said bistable sensor being cyclically activated during the motor rotation for the generation of a first binary signal correlated with said first and second states drivers;

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a circuit to generate a second binary signal correlated with the polarities of the alternating voltage for the circuit switched on;

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comprising the control unit by microprocessor signal inputs fed with said first and second binary signals, said control unit being programmed to determine the speed and direction of rotation of the motor, and to control the engine ignition, during rotation towards forward and reverse, and to reduce speed and reverse the motor rotation, based on information obtained from said first and second binary signals.

According to a particular embodiment of the invention, the bistable magnetic sensor is placed near a peripheral wall of the voltage generator rotor to be cyclically subjected to magnetic pulses to switch over their states, provided by means of flow circulation over the peripheral surface of the rotor, to obtain a binary signal that has positive and negative fronts appropriately outdated with with respect to the top dead center of an engine piston.

The magnetic sensor preferably comprises a bistable Hall effect probe, with a magnetic circuit suitable optimized to detect the magnetic flux with circula from appropriate openings in the peripheral wall of the rotor of the voltage generator; to maintain a high degree of accuracy in the sensor switching time, and at the same time ensure a satisfactory sensitivity, said openings for the flow passage They extend in the axial direction of the rotor.

The holes for the flow passage must be in such positions that the shafts of at least two holes consecutive are always facing the pole axes Magnetic voltage generator, having opposite polarities, at an angular distance correlated with the identified position by the top dead center of the piston or engine pistons.

More in particular, referring to the angular position of the rotor corresponding to the neutral point of a engine piston, the two openings that allow the activation of the sensor will be arranged symmetrically with respect to the position of the sensor itself, at an angular distance included approximately between 40º and 60º, so that the transitions in the conductive state of the magnetic sensor and the binary signal is produce in positions that are symmetrical with respect to the position identified by the top dead center of the piston, representing sufficiently advanced events with respect to neutral in both directions of rotation, thus allowing ignition control by operating even high feed angles in both directions of rotation.

According to a further aspect of the invention, the magnetic sensor is connected to the microprocessor of the unit control via an interface comprising a comparator of voltage capable of supplying said first binary signal in relationship with the state assumed by the bistable magnetic probe; the same line that supplies the control unit with information about the state of the magnetic probe is also used to supply energy to the probe itself.

According to an additional feature of the invention, the axes of the magnetic poles of the stator of the voltage generator must be positioned in such a way that the zero crossing of the alternating voltage supplied by it generator corresponds to the angular positions of the poles Magnetic rotor identified by the point or dead spots upper engine.

According to the invention, after a control of investment has been triggered by a vehicle driver or a user, the engine speed is reduced by controlling the ignition with an adequate ignition delay with respect to neutral superior, by means of an appropriate programmed deceleration law and controlled by the microprocessor, which acts on the extent of such delay; when the engine has reached a rotation speed Optimum preset, a spark is generated for ignition adequately and broadly ahead of the neutral superior, aimed at reversing the movement of the drive shaft before that the piston involved reaches its upper dead center, and then control the ignition with a usual optimal advance to allow the engine to continue turning in the opposite direction.

The device is able to detect the result of an investment attempt through processing, by the unit of control, of the signals provided by the magnetic sensor bistable and by the voltage generator, and is capable, by consequently, to control any subsequent attempt and, if it is necessary, to abandon the investment procedure, resuming normal progress control whenever certain conditions, such as the failure of a certain number of Attempts.

In addition, according to the invention, the order for motor inversion by the user is transmitted to the unit of control through an interface designed to control all inputs and outputs that interact with the user, being connected said interface to the ignition control unit by means of a serial communication channel.

Brief description of the drawings

The invention will now be described with more detail with reference to the examples in the attached drawings,  in which:

fig. 1 shows a block diagram that illustrates a two-stroke two-cylinder engine and a unit of electronic control according to the invention;

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fig. 2 shows a diagram indicating the operating mode of the bistable sensor used in the electronic device according to the invention;

figs. 3, 4 and 5 show diagrams illustrating the implementation of said bistable sensor using a probe bistable Hall effect, in three polarization conditions different;

fig. 6 shows a section view Large-scale cross section of a magnet voltage generator permanent, in its stator and rotor components, and of the sensor bistable magnetic, in which the axes of significant reference for the operation of the device according to the invention;

fig. 7 shows a block diagram of the ignition control unit according to the invention;

fig. 8 shows the wiring diagram of the magnetic bistable Hall effect sensor, in a phase where supplies power to the probe and simultaneously transmits information to the control unit about the status of the probe, using a single connection;

fig. 9 shows a possible solution of block designed to provide a correlated binary signal with the generator voltage;

fig. 10 shows the signal diagram binaries correlated with the state of the magnetic sensor and with the voltage generator output, provided that the motor rotates in a address;

fig. 11 shows the signal diagram binaries correlated with the state of the magnetic sensor and with the voltage generator output, provided that the motor rotates in the opposite direction to that of the preceding figure;

fig. 12 shows a diagram that represents the signals of the previous figures in the case of an attempt in the that the investment is successful;

fig. 13 shows a diagram that represents the signals of the previous figures in the case of an attempt in the That the investment is not successful.

Detailed description of the invention

Below is a description of a preferred embodiment of the apparatus and the procedure for inverting the rotation of a two-stroke internal combustion engine, according to the invention.

In general, the invention can be applied to any internal combustion engine, with one or more cylinders of a type of two times; however, the following describes the invention with special reference to a two-cylinder engine, with 180º regulation.

With reference to the diagram in fig. 1, has used reference 1 to indicate the flywheel rotor of a permanent magnet voltage generator that has a stator of twelve poles 2, provided with two stator windings 3 and 4 designed respectively, the first 3 to supply power to a unit 5 electronic control to control the ignition system, and the second 4 to supply power to the lighting system and the auxiliary equipment 6.

For simplicity of the drawing, the windings of the Stator 3 and 4 are shown schematically separated from the stator 2.

The engine in turn comprises a first piston P1 inside cylinder C1, and a second piston P2 inside the cylinder C2, which are mechanically connected in a manner known per se in opposite positions of an engine crankshaft, which in turn is operatively connected to rotor 1 of the voltage generator, such as It is shown schematically.

The apparatus of fig. 1 also comprises a flip-flop sensor 7, defined below, placed in such a way which faces the peripheral wall of the rotor 1, so that the magnetic field from the permanent magnets of the rotor, radially polarized with opposite polarities N and S, activates the same sensor 7 in sync with motor rotation, only when the flow generated by the magnets can cross and polarize the probe 7 through appropriate openings 8, which are provided in the ferromagnetic material cover of rotor 1 to deflect the flow.

The block 9 of fig. 1 identifies a regulator AC voltage designed to regulate the voltage produced by stator 4 winding to supply power for loads designed for lighting or other auxiliary functions, together shown in fig. 1 for block 6.

Figure 1 also shows a block 10 that represents a microprocessor unit to control the inputs  and the outputs of the device, which allows the driver of the vehicle or engine user interact with the system.

As previously mentioned, the device according to this invention contemplates the use of a single bistable sensor 7, to solve the problem of achieving an ignition system of digital control powered by a voltage generator, capable of get the reversal of the direction of motor rotation in so much that maintaining the maximum degree of control and knowledge of the angular position, the motor speed and its direction of rotation.

For the purposes of this description, the The intention of the expression "bistable sensor" is to indicate any type of magnetic or other sensor, sensitive to polarization of two different classes, for example of polarities or opposite signs, or of different levels, which is able to modify and maintain its own state and therefore also the signal output associated with it in one of the two configurations possible, in relation to the polarization that has been exerted on The sensor itself.

Another feature that the sensor in question to achieve the stated objectives is that a certain angular position of the engine drive shaft, and by consequently of the rotor connected to it, must correspond to a same type of sensor polarization, regardless of motor rotation direction.

The status diagram shown in fig. 2 is a schematic representation of the functional characteristic of this type of sensor, in which by "level 1" and "level 2" the possible states that can be assumed by the sensor output, and by "type A polarization" and "type B polarization" the possible polarization that can be detected by the sensor; their behavior can be described from the Following way:

Type A polarization : when the sensor detects this type of polarization, for example in the case illustrated, it detects the presence of a South magnetic pole through an opening 8 in the rotor, if the state of the output is at level 1, the status of the output will remain at level 1, while if the status of the output is at level 2, the status will be switched to level 1.

Type B polarization : when the sensor detects this type of polarization opposite the previous type, for example in the case illustrated, it detects the presence of a North magnetic pole through an opening 10 in the rotor; if the status of the output is at level 2, the status of the output will remain at level 2, while if the status of the output is at level 1, the status will be switched to level 2.

In the absence of both types of polarization, the sensor output remains in the current state, that is, it is not It produces switching from one level to another.

In the following description reference will be made, therefore, merely by way of example, to a magnetic sensor achieved using a bistable Hall effect probe whose element Sensitive 11 (figs. 3 to 5) is installed in a cylinder head suitable 12 of ferromagnetic material, which has three pieces of pole that follow each other angularly, facing the wall peripheral 13 of rotor 1; cylinder head 12 is attached to the body of the motor, as is the stator 2 of the generator, and is able to detect the magnetic flux of rotor 1 coming out of suitable openings 8 in the cylindrical wall 13 of the rotor 1; the openings 8 are preferably in the form of elongated holes in the direction of the Rotation axis of the rotor.

Referring to the previous description, and to figs. 3, 4 and 5, it can be seen that when the sensitive element 11 of the Hall probe faces an area of the peripheral surface 13 of a cup-shaped rotor 1 that lacks holes 8, as in fig. 4, gives rise to the condition indicated in fig. 2 for "absence of polarization", because the flow generated by the magnets N and S of the rotor circulates through the peripheral wall 13 of the own
rotor.

When, as in fig. 3, the axis of a opening 8 placed in correspondence with the pole of one of the N and S magnets of the rotor polarized radially in one direction, by example magnet S, is near the axis of sensor 7, coinciding with the axis of the sensitive element of the Hall probe, it gives rise to the condition conventionally indicated in fig. 2 as "type A polarization".

Finally, as shown in fig. 5 when the axis of an opening 8 placed in correspondence with one of the rotor magnets radially polarized in the opposite direction to above, for example magnet N, is near the axis of sensor 7, gives rise to the condition conventionally indicated in fig. 2 as "type B polarization".

In the case of application in an engine two-stroke two-cylinder, at 180º, as indicated schematically  in fig. 6, four openings 8A, 8B, 8C and 8D are made, angularly separated from each other as illustrated in fig. 6, where the position of rotor 1 is represented as corresponding at a displacement of 8º with respect to the position assumed by the rotor corresponding to the upper dead center of the piston P1.

Fig. 6 also shows the position of the stator 2 to uniquely define the phase of the transmitted signal by the winding of stator 3 that supplies power to the ignition, with respect to the output signal of the sensor 7 and with respect to the position of the top dead center (PMS) of the pistons P1 and P2

It can be seen that when the piston P1 reaches its PMS, that is, when the drive shaft and the rotor connected to it are rotate in a clockwise direction 8º with with respect to the position indicated in figure 6, the sensor 7 will be exactly in the middle of the arc between holes 8A and 8B, and the polar radii or extensions of stator 2 will be aligned with the shafts of the magnets N and S of the rotor; in fig. 6 shows the rotor displaced 8º in one direction in the opposite direction clockwise with respect to this situation, to prevent the axles of the cranks match those of the cylinders and make jeopardize the readability of the drawing.

Due to this situation, in correspondence with the top dead center a corresponding condition occurs of maximum magnetic flux through the stator windings, and therefore also a step for the zero crossing of the voltage generated in the stator windings.

Inside the control unit 5 is arranged a specific circuit 62 capable of generating a binary signal correlated with the polarity of the alternating voltage Vg for supply power to the ignition circuit, generated by the stator winding 3 as described below with reference to fig. 7.

The symmetrical arrangement of the two holes 8A and 8B and respectively 8C and 8D with respect to the axis of the sensor 7, in the conditions of the top dead center is advantageous because it does possible to generate two types of polarizations that can always be correlated with the generator voltage Vg to obtain information on the phase and on the direction of rotation of the engine, within a substantially symmetrical scheme in which it is Easy to control the ignition phase in both directions, making reference to a single sensor. This greatly simplifies the device, increases its operating reliability and reduces substantially its manufacturing costs.

With reference to figs. 7 and 8, below a more detailed description of the block diagram will be offered of the microprocessor controlled ignition control unit 5 constituting part of the apparatus according to the invention.

As shown in fig. 7, the unit of control 5 comprises a microprocessor 15 which is supplied in one of its inputs a first binary signal I1 coming from a input phase 16 connected to the magnetic sensor 7.

A second microprocessor input 15 receives a second binary signal I2 supplied by a phase of additional input 17 which has the function of providing a signal binary correlated with alternating voltage polarities Vg which supplies power to the ignition, powered by the winding of the stator 3.

Reference 18 in fig. 7 indicates an elevator voltage or booster transformer, while reference 19 indicates a power circuit to feed the various functional blocks

The output U of the microprocessor 15 is sent to the control electrode of an SCR electronic switch that constitutes  part of a conventional ignition circuit comprising the capacitor C connected to winding 3 through diode D1, the coil 20, for discharge in spark plugs 21, and the diode of D2 recirculation; therefore, the ignition circuit can be activated or deactivated by microprocessor 15 in a manner properly programmed to control engine ignition both during the conditions of normal rotation or rotation towards ahead, as during the rotation inversion, as well as during the rotation in the reverse direction of the motor. The case of fig. 7 shows, by way of example, a capacitive type ignition.

Fig. 7 also shows block 10 for the interface with the driver of the motor vehicle or the user, which It has the task of controlling all the inputs and outputs of the functions that involve the driver of the vehicle. The references 23 and 24 indicate the circuits by means of which the microprocessor 15 of the ignition control unit 5 and the microcontroller 25 of interface block 10, gain access to communications channel achieved by serial connection S.

In particular, the microcontroller 25 is programmed to detect when the driver operates the button investment indicated by INV, and to send an appropriate message to the ignition control unit 5 to drive the start of the investment procedure

Always, after ordering the reverse gear, that the engine is running in the reverse direction, such a change in status is communicated by microprocessor 15 to the microcontroller 25 of the interface 10, always by means of the serial line S; in in this case the microcontroller 25 activates an optical indicator or acoustic 26 to inform the driver that the vehicle is ready to go in the reverse direction to the normal direction, in other words, that the procedure for reversal of motor rotation.

The interface 10 also indicates the functional block 27 representing a circuit to supply energy to the device itself capable of extracting the necessary energy of winding 4 that supplies power to the lighting system and the auxiliary equipment 6.

It may seem that this solution is a complication compared to a system that controls directly, After direct connection to unit 5, a reverse button and an acoustic or optical indicator.

In the actual fact, wiring simplification of the system in general, and the possibility of supplying energy to any acoustic or optical indicator using alternating current of the stator winding 4 designed for the lighting system and The auxiliary team makes this solution competitive also from the cost point of view, especially when the function of Engine inversion is installed in an ignition system that it is already provided with other controlled inputs or outputs respectively by or intended for the driver of the vehicle. TO As an example, we can mention diagnostic functions of system sensing components, switches by means of which is possible to select particular operating modes system, inputs or outputs correlated with functions anti-theft integrated within the system.

Fig. 8 shows the sensor circuit bistable magnetic 7, composed of a bistable Hall probe and the electronic components by means of which it is possible obtain from the probe itself the binary signal I1 destined for the microprocessor 15 and simultaneously supply power to the probe 7 by means of a single connection, in addition to the connection to land.

It can be seen, in fact, that in itself the sensitive element 11 constituting the sensor core 7 so far called "bistable Hall probe" is provided with three contacts intended respectively for the power supply E, ground connection M and output U1. He behavior of these elements sensitive to a magnetic field, referred to by various manufacturers as "switches bipolar "or" digital position sensors "or" bolts Precision Hall effect "is to have two stable states corresponding respectively to a low and high impedance at earth of the output contact, and in this sense also denominated as "switches", and switching between these two states when they are polarized by a magnetic field with a certain polarity and over a certain intensity threshold.

According to a particular feature of this invention, a single conductor is used both to supply power to the magnetic sensor to get its output signal.

In this regard, contact E to supply power to the Hall 11 probe is connected, by wiring appropriate and a resistance R2, to a DC voltage source Vcc fed by block 19 of fig. 7.

In the same figure it can also be seen that, arranged between output U1 and input E that supplies power to the Hall 11 probe, there is a parallel circuit comprising a resistor R1 designed to allow the circulation of a current the through the probe when its output U1 is in one of the states contemplated, particularly in the state corresponding to a low impedance of the M earth contact.

The voltage V2 representing the division of the voltage Vcc with respect to R2 and the equivalent impedance of the probe 11 to ground, is also provided in the negative input of a voltage comparator 30, whose positive input is provided with a reference voltage U1 resulting from a division of the voltage Vcc defined by resistors R3 and R4.

The voltage comparator 30 in turn supplies a signal I1 at its output in the form of a binary signal which is then supplied to a corresponding input of microprocessor 15 of fig. 7.

The operating principle on which it is based the circuit of fig. 8 can be described as follows: resistors R1, R2, R3 and R4 are sized in such a way that when the sensitive element 11 of the Hall probe is in its state low impedance, the voltage V2 present in the negative input of the voltage comparator, equivalent to Vcc - I x R2 with I equal to the current Is that feeds the probe, added to the current Ia absorbed by the U1 output of the probe through R1, is less than the voltage V1 that invariably assumes the value given by the Vcc expression x R3 / (R3 + R4); this obviously leads to a value "high" of the output I1 of the voltage comparator 30. At the inverse, when the sensitive element 11 is in its high state impedance, current I is composed only of current Is to feed the probe, resulting in a V2 greater than V1 and, therefore, a low value of output 11.

With reference to fig. 9, then it provides a description of a possible embodiment of block 17 of fig. 7 which has the function of providing the binary signal I2 correlated with the polarity of the alternating voltage Vg generated by winding 3 to supply power to the ignition.

As shown in fig. 9, the block 17 comprises a transistor whose base is polarized by means of the resistor R5 with the voltage Vg coming from the winding 3 of the voltage generator, and respectively with a constant voltage representing a division of the voltage Vcc supplied by a resistor R6. In turn, the collector-emitter circuit of transistor TR is connected to circuit 19 to supply power to the various functional blocks, by means of the resistor for dividing the input voltage Vcc, grounded respectively; in this way, at the output of block 17 a binary signal 12 is supplied whose phase is correlated with that of the voltage Vg of the
generator.

Next, the mode of operation of the described apparatus, both in the case of normal engine operation, that is, with rotation towards front, as in the case of its operation with rotation inverted, with reference to the graphs in figs. 10 and 11. These diagrams show the evolutions of the I1 signals associated with the state of the bistable magnetic probe 7, and I2 associated with the voltage Vg to supply power to the ignition circuit a as the angular position α of the drive shaft evolves with respect to the case of regulation, in both directions of rotation.

The engine rotation speed, as well as the events that uniquely determine the angular position of rotor 1 capable of allowing adequate digital control of the ignition on both directions of rotation can be determined using the binary signals I1 and I2.

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Referring to fig. 10 showing the diagrams related to a forward rotation of the engine, The following observations can be made:

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the negative fronts of signal I1 correspond to an angular position that advances 53º the PMS of one of the cylinders of the engine, by example cylinder C1;

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the positive fronts of signal I1 correspond to an angular position which is delayed 53º with respect to the PMS of the referred C1 cylinder in the preceding point;

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he first negative front of signal I2 that follows a negative front of signal I1 corresponds to an angular position of the rotor that matches the PMS of piston P1 of cylinder C1 of reference;

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it is obvious that the microprocessor 15 programmed to recognize these events, you can also get Easily rotate speed by measuring elapsed time between two of the events described above.

Referring to fig. 11 showing the diagrams related to an inverse rotation of the motor, can make the following observations:

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the positive fronts of signal I1 correspond to an angular position which advances 53º the PMS of the reference cylinder C1.

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the negative fronts of signal I1 correspond to an angular position which is 53º behind the PMS of the cylinder reference mentioned above;

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he first negative front of the I2 signal that follows a positive front of signal I1 corresponds to an angular position of the rotor that matches the PMS of piston P1 of cylinder C1 of reference;

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it is also obvious in this case that the microprocessor 15 programmed to recognize these events, You can also easily obtain the rotation speed by measuring the time elapsed between the two events described previously.

Looking again at the diagrams in figs. 10 and 11, it can be seen that, in the case of forward rotation, the negative fronts of the signal I1 always occur when the signal I2 is low, and the positive fronts of the I1 signal are always occur when the I2 signal is high, while in the case of reverse rotation the positive fronts of the signal I1 always occur when the I2 signal is low, and the negative fronts of the I1 signal always occur when the I2 signal is high.

It is extremely simple, therefore, through of an appropriate control program carried out by the microprocessor 15, using this criterion, determine the direction effective engine rotation.

It can be seen that, as it is possible to recognize associable events with angular positions sufficiently advanced with respect to PMS, the program carried out by the control microprocessor 15 can control the advance of the on, defining an appropriate delay corresponding to a certain phase angle indicated in figs. 10 and 11 by α in both directions of rotation; having the possibility of identify events that correspond to positions close to the PMS it is possible to activate the ignition in a suitable defined position even if, due to the cyclic irregularity of the engine, no it is possible to have the necessary precision when establishing a correspondence between arcs and times, all this in both directions of rotation; it is also possible to identify immediately the direction of rotation with the greatest certainty, all this with the use of a single sensor, through the simple resource of proper regulation of sensor 7 and the relevant openings 8 for its activation, both with respect to the duty cycle of the motor as with respect to the signal to supply the circuit of Power on from the generator.

The use of conventional systems or systems known from the previous documents does not lead to the achievement of these results, or in any case leads to less reliable results by the use of more than one sensor, due to both the characteristics intrinsic of the sensors used, such as the fact that extremely low speeds or approximately at the time of inversion, algorithms based on the correspondence between arcs and angles become critical, leading to the production of systems that under certain conditions can be functionally efficient, but they are undoubtedly more expensive and more critical in As for your configuration.

All this is obvious through the device according to this invention that contemplates the use of a single magnetic sensor flip-flop, activated by the flow of the same magnetic field as well as the voltage generator, due to the symmetry of the magnetic system with respect to the engine cycle it contemplates, in the position of the rotor corresponding to the PMS of the pistons, a central position of the magnetic probe 3 with respect to the two holes 8A and 8B u 8C and 8D provided to activate the sensor, and the shaft placement of magnetization of the rotor magnets in correspondence with the axes of the stator radii.

The system previously described by means of which apparatus according to this invention is capable of establishing the motor rotation direction, essentially serves to determine if the engine inversion procedure has been successful or not, in in which case the microprocessor 15 can trigger new attempts or abandon the investment, continuing to control the ignition on the current address depending on whether certain occur conditions or not, such as the detection of a rotation speed excessively low, or the failure of a number of attempts preset

Fig. 12 shows the evolutions over time of the binary signals I1 and I2 correlated respectively with the output of the magnetic sensor 7 and with the voltage Vg generated by the stator winding 3 designed to supply power to the ignition circuit, corresponding to a maneuver of investment carried out successfully from a condition of forward rotation until a reverse rotation condition; it can be seen that after the investment spark activated in the instant T1, and therefore in advance with respect to the PMS of the piston P2 (it should be borne in mind that in the example in question the negative front of the signal I1 that precedes T1 is advanced 53 degrees with respect to the PMS of the C2 cylinder), the front  subsequent positive of the signal I1 is detected at time T2 when the signal I2 is low; This condition indicates that the investment has taken place correctly and that the system must therefore blow the next spark on the next negative front of the signal I2 close to the PMS of the cylinder C1, starting the control correct ignition in the reverse direction.

Fig. 13 shows the evolutions over time of the binary signals I1 and I2 correlated respectively with the output of the magnetic sensor 7 and with the voltage Vg generated by the stator winding 3 designed to supply power to the ignition circuit, corresponding to a failed attempt to inversion while the engine is turning in one direction towards in front of; it can be seen that after the investment spark activated at time T1, and therefore in advance with with respect to the PMS of the P2 piston (it should be remembered again that the negative front of the signal I1 that precedes T1 is advanced 53 degrees with respect to the PMS of cylinder C2), the subsequent positive front of the signal I1 is detected in the instant T2 when the signal I2 is high; this condition indicates that the investment has not taken place and that the system must, so So, decide whether to skip the next spark with a certain delay with respect to the subsequent negative front of signal I1 to carry out a new investment attempt, or after the appearance of the first negative front of the I2 signal that follows the negative front of the I1 signal to form the spark near the PMS of cylinder C1, continuing the correct ignition control in the forward direction.

A description of how the apparatus according to this invention performs the maneuver that It leads to reversal of motor rotation:

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while maintaining the engine operating at minimum rpm, activating the INV control first the ignition spark formation regulation is modified controlled in a manner programmed by microprocessor 15 to get a reduction in rotation speed. In particular, in this phase contemplates a certain delay in the formation of spark with respect to the PMS of the engine pistons, that is, when the piston has already begun its downward career; this maneuver it implies a reduction of the energy available to supply energy to the motor rotation, thus reducing the speed;

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when the rotation speed, after the maneuver described previously, it is sufficiently low, or less than a given threshold properly programmed in the electronic control unit, it will generate a spark of ignition, considerably in advance with respect to the PMS of a piston, which, activating combustion considerably in advance regarding the optimal regulation for normal engine operation, that is, when the piston is going up and has not yet reached the normal forward position with respect to the PMS of the piston itself, for example with an advance between 20º and 60º, it will develop a high pressure during the compression phase leading to a negative work aimed at Reversal of the direction of rotation, before the piston reach your PMS;

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after generating the spark aimed at investment, as described in the preceding point, the system will check the result of the investment attempt processing the binary signals I1 and I2 at the outputs of the microprocessor 15 to determine the direction of rotation of the engine as previously described: if the investment attempt has succeeded, the system takes care of the correct control of the on in the new direction of rotation, and it is considered to be the investment operation has ended; yes, on the contrary, it recognizes the failure of said investment attempt, the system is capable to control a certain number of new attempts before leaving the investment operation, continuing the normal control of the lit in the current address.

As part of the apparatus according to this invention is the unit identified by block 10 in figs. 1 and 7 designed to control the system inputs and outputs, which are aimed at interacting with the user or driver of the vehicle; This unit integrates or is connected to all inputs and outputs involved in the interaction of the system with the user that are contemplated by the specific application; in particular, fig. 7 shows the investment inversion control button INV and the acoustic indicator reverse rotation 26 in that they are the only devices of this type directly involved in the description of this invention.

The unit 10 of fig. 1 is described with greater detail in fig. 7 showing the programmed microprocessor 25 properly to communicate through an interface circuit 24, via the serial communication line S, and the interface 23, with unit 5 to control the ignition, as well as to monitor the activation status of the INV buttons and the switches 28 integrated in device 10 or connected of another way to it, to send, through the line of S communication, appropriate messages to microprocessor 15 of the control unit, and programmed to receive information from of unit 5 related to its operational condition and for control the screens, indicators or more in general the outputs associated with the operating condition of the ignition system.

The diagram of fig. 7 also shows the block 27 representing a circuit that supplies power to the unit 10 for driver interaction, and any indicator optical or acoustic controlled by it, obtaining energy required from winding 4 designed to supply power to the lighting system and auxiliary equipment.

To consider the objectives of this solution within the scope of motor vehicles for which This invention is intended, we would like to explain some how many observations of a general nature related to reference applications:

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he type of application makes it extremely important that the unit of ignition control is extremely light and compact;

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is important that the connections contemplated in the area of Engine compartment is airtight or with a high degree of protection against environmental agents such as splashing water, dirt and various chemical agents;

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the devices designed to control the motor, such as phase sensors or other sensors designed to increase accuracy and efficiency of the ignition control, such as temperature sensors, sensors position of the fuel supply regulating valve or detonation sensors are always placed in the compartment of the motor and therefore near the control unit of on which, as in our case, also integrates the coil of on, it is placed near the spark plugs; the switches, buttons and any optical or acoustic indicator or indicators that show the operating parameters of the ignition designed to system interaction with the driver are obviously placed near the driver;

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the acoustic and optical indicators and, in general, the devices of display involve comparable electrical inputs and sometimes much higher than the typical entries of even the most Sophisticated ignition circuit.

In the light of the preceding observations, it is of course, the solution proposed according to this invention, in addition to solve the problem related to the supply of energy to outputs (bulbs, screens or acoustic indicators) because the winding 5 designed to supply power to the lighting system and the auxiliary equipment provides a power supply totally sufficient for this purpose, it also allows a considerable rationalization and simplification of the wiring of the system, which results in a significant reduction of costs

It can also be seen that modularity like this introduced allows greater economies of scale and simplification of production management in the case of the range of applications that contemplate more or less complex configurations of devices for interaction with the driver.

From what has been described, it will result It is clear that the invention is directed to a method and to a electronic device for reversing the direction of rotation of a internal combustion engine as defined; the invention It is also aimed at a kit to equip a combustion engine internal by means of an electronic device for inversion of the direction of rotation of the motor comprising a control unit by microprocessor, programmed to control the ignition phase both during forward rotation and during rotation inverse, as well as to control the investment procedure of rotation, based on information obtained from a first signal binary emitted by a bistable magnetic sensor activated by the magnetic flux of the generator, and by a second binary signal correlated with generator voltage: it is made to be reverse the direction of rotation by entering a delay in the ignition, and subsequently generating an advanced spark while the engine is still turning in the original direction; This solution allows the device to be applied initially without the microprocessor controlled unit 10 to control the inputs and outputs of the electronic control unit 5, as in a normal ignition system. The unit controlled by microprocessor 10, to control the motor inversion, also It can be applied later.

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References cited in the description

This list of references cited by the Applicant is only for the convenience of the reader. Not a part of the European patent document. Although it has been taken special careful in the compilation of references, cannot be excluded errors or omissions and the EPO rejects all responsibility to this respect.

Patent documents cited in the description

US 5036802 A [0003]

US 5782210 A [0003]

US 5794574 A [0003]

Claims (23)

1. Procedure to reverse the rotation of a two-stroke internal combustion engine that has a voltage generator (1, 2) to generate an alternating voltage (Vg) that has different polarities for an ignition circuit (20, 21), and an electronic control apparatus (5) comprising a microprocessor unit (15) for controlling the alternating voltage (Vg) supplied to said ignition circuit (20, 21), in which the rotation inversion is made after a reduction of the motor rotation speed, characterized by the stages of:

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provide said control apparatus (5) a bistable sensor (7) that has first and second states conductors, and cyclically switch the sensor (7) between said first and second states during engine rotation;

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generate a first binary signal (I1) which has first and second operational levels correlated with said first and second conductive states of the bistable sensor (7);

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generate a second binary signal (12) which has first and second operational levels correlated with the polarities of the alternating voltage (Vg) supplied to the circuit ignition (20, 21);

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detect the speed and direction of motor rotation, based on information obtained by the unit microprocessor control (5) from said first (I1) and second (12) binary signals;

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reduce the rotation speed of engine while still turning in the direction detected, delaying the spark formation of the ignition circuit (20, 21) with respect to an upper dead center of the engine; Y

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make a rotation inversion of the motor forming the spark in advance, with respect to that point top engine dead.

2. Method according to claim 1, characterized by the step of reducing the speed of rotation by delaying the ignition of the engine, with respect to the upper dead center, changing the extension of the ignition delay according to a deceleration procedure programmed in said control unit by microprocessor (15). 3. Method according to claim 1, characterized by the step of recognizing, by means of said microprocessor control unit (15), the event of inverse rotation of the motor based on information obtained from said first and second binary signals (I1, I2 ), and continue normal control of the ignition sparks to maintain the inverted direction of rotation of the motor. Method according to claim 3, characterized by the step of recognizing the inverse rotation of the motor in relation to a low condition of the binary signal (12) correlated with the voltage (Vg) of the generator, in correspondence with the first positive front of the binary signal (I1) emitted by the bistable sensor (7), after the activation of an inversion spark. 5. Method according to claim 1, characterized by the step of recognizing, by means of said microprocessor control unit (15), a failed reverse rotation of the motor based on information obtained from said first (I1) and said second (12) binary signals, and cause the repetition of at least a second phase of rotation inversion. Method according to claim 5, characterized by the step of detecting a failed rotation inversion in relation to the binary signal (12) correlated with the generator voltage, and the first positive front of the binary signal (I1) emitted by the flip-flop sensor (7), after activation of an inversion spark. Method according to claim 1, in which the voltage generator comprises a stator winding (2) and a permanent magnet rotor (1) to provide a magnetic excitation field, characterized in that said first binary signal (I1) is generated by a bistable magnetic sensor (7) cyclically switched to its first and second conductive states by the magnetic field of the same rotor (1). Method according to claim 7, according to which the voltage generator comprises a cup-shaped rotor (1) having a peripheral wall (13), characterized in that the bistable magnetic sensor (7) is switched to its first and second conductive states by magnetic fluxes of opposite polarities, through angularly separated openings (8) in the peripheral wall (13) of the rotor (1). 9. Electronic device for investment of rotation of an internal combustion engine that has at least one two-stroke cylinder-piston unit (P1, C1; P2, C2), comprising:

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a engine ignition circuit (20, 21);

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a voltage generator that has a permanent magnet rotor (1) and a stator (2) provided with a winding (3) to generate a voltage alternate (Vg) to supply power to the ignition circuit (20, twenty-one);

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media to supply phase signals correlated with the direction and motor rotation speed; Y

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a microprocessor control unit (15), to control the phases of spark formation of the ignition circuit (20, 21) and for make a reversal of motor rotation,

characterized by understanding:

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a bistable sensor (7) that has first and second conductive states, said bistable sensor (7) being cyclically activated during the motor rotation for the generation of a first binary signal (I1) correlated with said first and second states drivers;

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a circuit to generate a second correlated binary signal (12) with the polarities of the alternating voltage (Vg) for the circuit on (20, 21);

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comprising the control unit by microprocessor (15) signal inputs fed with said first and second binary signals (I1, 12), being programmed said control unit (15) for determining the speed and direction of rotation of the motor, and to control the ignition (20, 21) of the engine during forward and reverse rotation, and for reduce speed and reverse motor rotation based on information obtained from said first and second signals binary (I1, I2).

An apparatus according to claim 9, characterized in that said bistable sensor (7) comprises a magnetic probe activated by the magnetic field of the voltage generator (1, 2). 11. Apparatus according to claim 10, characterized in that said magnetic sensor (7) comprises a bistable Hall probe. An apparatus according to claim 9, characterized in that said microprocessor control unit (15) is programmed to determine the direction of rotation of the motor in relation to the states of said second binary signal (I2) and in correspondence with the ascending and descending from the first binary signal (I1). 13. Apparatus according to claim 9, wherein said bistable sensor (7) comprises an activated magnetic sensor by a magnetic flux of the voltage generator (1, 2), and in which the rotor (1) of the voltage generator comprises a wall peripheral (13) to hold a plurality of polarized magnets radially they have alternating poles (N, S) of polarities opposite, characterized in that the rotor (1) comprises at least a first and a second circulation means (8) for flow circulation to the sensor (7) that can be aligned with oppositely polarized magnets (N, S) angularly separated on the peripheral wall (13) of the rotor (1). 14. Apparatus according to claim 13, characterized in that said flow circulating means comprise angularly separated openings (8) in the peripheral wall (13) of the rotor (1). 15. Apparatus according to claim 14, characterized in that said openings (8) for the magnetic flux extend in the direction of the axis of rotation of the rotor (1). 16. Apparatus according to claim 13, characterized in that said first and second flow circulation means (8) are arranged in the peripheral wall (13) of the rotor (1) in a symmetrical position with respect to the magnetic sensor (7), in the condition of the top dead center of a piston (P1, P2) of the engine. 17. Apparatus according to claim 16, characterized in that said first and second flow circulation means (8) are arranged in an angular space between 40 ° and 60 °. 18. Apparatus according to claim 9, wherein said bistable magnetic sensor (7) comprises an input and a output for a control signal correlated with the first and second conductive states of the sensor (7), characterized in that a resistive circuit (R1) is connected bypass between said sensor input and output (7), and that the sensor input and output (7) are connected to a voltage power supply (Vcc) respectively to a voltage comparator (30) for generating said first binary signal (I1), by means of a single conductor. 19. Apparatus according to claim 9, characterized in that the axes of the magnetic poles (N, S) of the stator (2) are positioned such that the zero crossing of the alternating voltage (Vg) supplied to the ignition circuit (21) corresponds to the angular positions of the magnetic poles (N, S) of the rotor (1), corresponding to the top dead center of a piston (P1, P2) of a cylinder (C1, C2) of the engine. 20. Apparatus according to claim 9, characterized in that it comprises a microcontroller (25) for managing the input and output interacting with a user, connected to the ignition control unit (15). 21. Apparatus according to claim 20, characterized in that said microcontroller (25) is connected to the ignition control unit (15) by a serial connection channel (S). 22. Apparatus according to claim 9, characterized in that said ignition control unit (15) is programmed to generate a spark for the rotation inversion, which has an advance between 20 ° and 60 °, with respect to the upper dead center of the motor . 23. A rotation inversion kit for upgrade an internal combustion engine that has at least one two-stroke cylinder-piston unit, which it comprises an apparatus according to one of the claims from 9 to 22